SBC 350 timing chain not installed right?

Discussion in 'The "Other" Bench' started by azstage1, Jan 30, 2017.

  1. azstage1

    azstage1 Chris Jones

    I have a couple of GS's but I need help with my 73 Z28. Engine was running great when I pulled it in OCT to reseal everything and repaint. After putting back in, I have a noise while cranking, and running. Tink Tink Tink Tink etc.. Getting some contact internal. I did not remove any internal while engine was out. I did remove the cam gear and timing chain but left the crank gear on it. I thought I took care to put back before anything was moved. Could I have gotten the cam out of sync with the crank?

    Yesterday I did a compression test. I also just noticed I have oil dripping from my passenger side exhaust at the seam where the down pipe meets the level portion of the pipe. Is this pointing to the timing chain being reinstalled wrong?
    Compression Test:
    1 - 140 2 - 145
    3 - 142 4 - 145
    5 - 140 6 - 115, again at 92
    7 - 130 8 - 140

    Appreciate any assistance. Not getting any responses on the chevy board so far.
  2. LouV

    LouV Silver Level contributor

    You may have a problem with the chain cover and the chain. I would take that off and make sure everything is OK on the cover and there is nothing bent. Check especially the seal at the bottom of the cover. Also check and double check the cam timing marks to be sure they are exactly lined up. They are easy to get one tooth off. Measure with a straight edge.Is the chain good? A stretched chain can be bad.

    I would also pull the right valve cover and check everything on that head to see if anything is not installed right. I would also check for an oil leak that could be the cause for the oil on the exhaust pipe.

    Try to find exactly where that "tink" is coming from. It could be something hitting the flywheel, or something hitting the alternator fan to a rocker arm stud pulled out. Unless you can find that problem of the noise quickly I would be very tempted to pull the motor again and check it where I can see everything clearly and work on it in good light.

    Good Luck.

  3. azstage1

    azstage1 Chris Jones

    Thanks Lou. All of this engine stuff is not so much in my comfort zone and I hate have to redo stuff especially gaskets. It will be much easier once the engine is out but dang....I hate to pull it back out after I just put it in and hook every single thing back up before noticing the problem. I have to drop the oil pan partially to get the front cover off. I may do that with it in the car cuz if the timing gears don't line up properly I'll know that is the issue and I"ll just fix and put back together. Timing set is good and not the original. I used "the right stuff" to seal everything so that will make it hard to unseal as well.
  4. DeeVeeEight

    DeeVeeEight Well-Known Member

    You can try using a mechanic's stethoscope to help isolate the noise. If you don't have one you can make one.
  5. azstage1

    azstage1 Chris Jones

    Just to wrap this one up..... I found the noise. It was the rear crank flange area rubbing the 4 speed inspection cover. I just had to bend it out of the way. I was also thrown off by the amount of smoke I was getting with was due to two new exhaust donuts and some oil that had gotten in the right side exhaust.

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